Double jointing of pipe has been a relatively expensive and complicated operation. Since proper and adequate double jointing of pipe requires that an internal weld be formed to join the two pipe sections together, it has been necessary to move both men and equipment into the pipes to perform the internal welding operation. Proper aligning of the pipe sections prior to welding has been a tedious and cumbersome operation, and the moving of welding clamps and internal welding apparatus into the pipes has been arduous and expensive. Movable support apparatus for the clamp and internal welder has been necessary, requiring tracks or other movable supports which occupy considerable space and are relatively expensive. This invention seeks to reduce both the cost of the equipment which is necessary and the number of personnel required to operate the equipment.